Insulin Therapy After Cardiac Surgery

Palo Alto (17 mi)

Overseen byRoupen Hatzakorzian, MD

Age: 18+

Sex: Any

Travel: May be covered

Time Reimbursement: Varies

Trial Phase: N/A

Waitlist Available

Sponsor: McGill University Health Centre/Research Institute of the McGill University Health Centre

No Placebo Group

Trial Summary

What is the purpose of this trial?Background: The hyperinsulinemic-normoglycaemic clamp technique is a precise method of providing insulin and glucose while maintaining normoglycemia. High-dose insulin has profound effects on glucose and protein metabolism. It has been demonstrated in coronary artery bypass graft (CABG) surgery patients that high-dose insulin causes hypoaminoacidaemia. The investigators hypothesize that the reduction of plasma amino acids (AAs) levels as seen in patients undergoing CABG surgery and receiving high-dose insulin is a consequence of an inhibition of whole body proteolysis as assessed by L-\[1-13C\]leucine tracer kinetics. Objective: The present study aims to investigate the effect of high-dose insulin therapy on whole body protein, glucose and end-organ metabolism in patients undergoing CABG surgery using stable isotope tracers \[6,6-2H2\]glucose, L-\[1-13C\]-leucine and L-\[2H5\]phenylalanine. The changes in the metabolic-endocrine milieu will also be evaluated by plasma concentrations of glucose, lactate, free fatty acids, prealbumin, albumin, fibrinogen, insulin, glucagon, and cortisol. Methods: With the approval of local institution's ethical committee, 30 patients scheduled for elective will be enrolled. The patients will be divided randomly into two groups. The control group will receive a standard IV insulin protocol with the aim of keeping blood glucose \< 10 mmol/L. The treatment group will be administered a high dose insulin infusion of 5 mU/kg/min coupled with a variable infusion of glucose to maintain normoglycemia (4-6 mmol/L). Insulin infusion will be continued until the end of the study period approximately 8 hours after surgery. L-\[1-13C\]leucine and \[6,6-2H2\]glucose kinetics will be used to assess changes in whole body protein and glucose kinetics. Hepatic albumin synthesis will be determined by using primed continuous infusion of L-\[2H5\]phenylalanine. The preoperative measurements will be performed on the morning before the surgery. Postoperative studies will be conducted two hours after arrival in the intensive care unit. Tracer kinetics between the two groups will be analyzed using ANOVA for repeated measurements. Significance: High-dose-insulin results in a significant reduction in plasma AAs in cardiac surgery. This study should address if this drop in plasma AA levels is secondary to a decrease in breakdown, an increase in synthesis or both during high-dose insulin therapy in open heart surgery.

Eligibility Criteria

This trial is for patients who can consent and are undergoing elective cardiac surgery, specifically CABG. It's not suitable for those with severe malnutrition or obesity (BMI <20 or >30), significant weight loss in the past six months, or chronic liver failure.

Exclusion Criteria

I am not severely underweight or overweight and have not lost more than 10% of my body weight involuntarily in the last six months.

I have chronic liver failure.

Treatment Details

The study tests high-dose insulin therapy on protein and glucose metabolism during CABG surgery. Patients will be split into two groups: one receiving standard insulin to keep blood sugar under control, and another getting a high dose of insulin plus glucose to maintain normal blood sugar levels.

2Treatment groups

Experimental Treatment

Active Control

Group I: High-dose insulinExperimental Treatment1 Intervention

Group II: ControlActive Control1 Intervention